Centrifugal fan and pump.



S. C. DAVIDSON. CENTRIFUGAL' FAN AND PUMP.

APPLICATION man 05c. 16. 1902.

Patented June 15, 1915.

3 SHEETSSHEET 1.

w/ TE s55 3 y Afowneys,

I s. c. DAWDSON.

CENTRIFUGAL FAN AND PUMP.

APPLICATION FILED DEC. 16, I907.

l; ,3@59 I PatentedJune 15, 1915.

3 SHEETSSHEET 2. fly. 0

WI mm S. C. DAVIDSON.

CENTRlFUGAL FAN' AND PUMP.

APPuc/(non man DEC. I6. 1907.

mm June 15, 1915.

3 SHEETS-SHEET 3.

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INVENTOR r gm LL m SAMUEL CLELAND DAVIDSON, F BELFATST, IRELAND, ASSIGNOH, BY TJIESNE ASSIGIL' MEN'TS, T0 AMERICAN BLOWERCOMPANY, 0F GREEN ISLAND, NEW YQBSK, A (J6E- PORATION 0F NEW YORK.

cnnsnrruean FAN AND PUMP.

To all whom it may concern:

lie it known that I, SAMUEL CL LAND' DAVIDSON, of Sirocco Engineering Works, Belfast, Ireland, merchant, have invented certain new and useful Improvements in Centrifugal Fans and Pumps, of which the following is a specification.

' My improvements'relate to the blades or Specification of Letters Patent.

Application filed December 16, 1907, denial its. $38,658.

mentioned patent. The invention is applicable to any of the types of blade illustrated in such patent which are fiat, curved or bent 1n cross section. It is also applicable in those blades which are parallel sided or taperedeither in their original fiattened'c'r blank form or in their completed form. The

blades are preferably twisted or extended in vanes of centrifugal fans or pumps (here a helical or curved line, so that the disk end inaiter called fans) wherein the fluid operated on enters axially and centrally and is discharged circumferentially, and said improvements are more particularly applicable to fans of the type described and shown in the 'specificationof my prior United States Patent No. 662,395, dated 27th, November, 1900.

I have found in practice that in centrifugal tans and particularly in those of the multi bladed type there isa tendency to set up a centripetal movement of the air at that I end of the fan into which the fluid enters (hereinafter called the intake end of the fan). This tendency is particularly noticeable when the blades are given the best shape to produce the maximum centrifugal efiect, namely, when the outer edges are inclined forwardly in the direction of rotation.- At the intake ends of the blade this forward inclination is apt to increase the centripetal action by cutting into the stream of fluid and \vcdging it inward. I have foundthat, if the disk end of the blade (or that end of the blade which is opposite the tent than the intake end of the blade.

intake end) has its outer edge extended in' the direction of rotation'in advance of the same edge at the intake end. this tendency is to a considerable extent counteracted: The best results are obtained, however, when the disk end of the blade is inclined forwardly in the direction of rotation to a greater exy preference the intake end of the blade has its outer edge inclined even to a certain extent rearwardly in a direction opposite the direction of rotation, so that a distinct cub \vardly wcd'ging action takes place at the intake end of the fan, entirely counteracting the tendency to centripetal flow at the end of the fan where this tendency exists; while the remaining parts of the blades are shapcd of the blade extends forwardly in the direc' tion of rotation, While preferably theintake end extends rearwardly, that is to say, with its inner edge leadlng its outer ed e.

" Reference to the following drawings will more fully explain the nature of my invention, and how same is carried into effect.

Figure 1 is a perspective View of the improved fan Wheel. Fig. 2 is a similar View to Fig. 1 having the blades formed in two parts in alinemcnt. Fi is a part eleva tion of the improved an Wheel shown :in Fig.1 looking into the intake and showing some of the blades in section and others in end elevation. Fig. i is a part view of Fig. 1' in section. Fig. 5 is a plan view of one of the blades shown in Fig. 1. Fig. 6 is a part sectional elevation of the improved fan Wheel shown in Fig. 2. Fig. 7 is a part sectional View of Fig. :2. Fig. 8 is a plan of a blank form showing a parallel sided blade. I Fig. 9 is a similar plan showing tapered blade. Fig. 10 is a plan view of aZsingle-blade composed-of several sections mounted upon suitable rings. Fig/11 is a section of a bent or angular blade taken close to the intake end, and showing the disk end extended forwardly in the direction of rotation. Fig..12 is a similar view of a warped blade made of flat plate showing the disk end extended forwardly, and the in take end extended rearwardly. p That part of the blades which is farthest from the ihtake Willhe referred to as the disk end being usually attached to r. disk as shown; that end of the blades which and small radial depth, and inclosc .a central cylindrical intake chamber. The line of the outer, and that of the inner edges of; the blades a instead of being substantially inc parallel to one another, and to the axis of the fan as in the prior patent referred to,

cross'one another at twisted to this extent like anArchimedean is shown the section of the b screw. 7) is the part of the blade which is at the disk end, and farthest away from the intake end of the fan and 0 the part nearest the intake end. (Z is the outer edge or tip of the blade at the part I) while a is the outer edge of the blade at the part 0. d and c are respectively the inner edges of the respective ends of the blades. The blades are so set that the part d of the outer edge is farther forward in the direction of rotation than the corresponding part c at the intake end, and the inner edge at cl is behind the corresponding edge at e.

In Fig. 3 at 1 is shown the section of the blades at or near the disk enIdS and at '2 ades at the intake endat 4 is shown an end view of the blades looking from the intake end with the connecting ring (5) broken; away. This said ring is employed to connect the intake ends of the blades together. Other forms of this ring may be employed as described in the said prior patent.

Referring to Figs. 2, 6 and 7, which illustrate another modification of the blades, 7 is an annular disk dividing the blades into two sections a and a", a. being the section which is at the disk end and farthest away from the intake end of the fan. The outer and inner edges 41 and d e of the blades a and a respectively are approximately parallel but so set in relation to each other that the outer edges cl of the sections a," at the disk end project 'in advance of the inner edges d in the direction of rotation, while the inner edges 6 onthe other section at the intake end of the blades is in advance of the These figures show a fan lengths, but they may be of unequal lengths or more than two sections may be employed all the sections may be in alinement, and the outer edge of each section may be set forward relatively to the preceding one in step like formation, progressively advancing fr ojm the eye end toward the disk end thus giying the screw effect previously des c j i'ibed; p eferably be fitted between each pair of scc ti ns, and the ends of the blade sections at tached'thereto, but it will be obvious that the several sections in alinement-may, if required, be fastened the one to the other. Such a construction is shown in Fig. 10. In this constructioiithe blade is formed in three sections, one ofwhicli d is next to the disk endoftliel fan and is tiltedfon of blades of equal an annular disk such as f will wardly in the direction of rotation. The second (1 approximates one of the radii of the fan, and a third section (Z is tilted rearwardly. lhe disks f f and f serve to support the ends of the various sections.

The cross section of the blades in the above described Figs. 1, 3, a and 5, is curved, but my invention is also applicable to blades which are so angled in cross section as to form a. shallow trough, an example being shown in Fig. 11, or to blades which in cross section are approximately flat or radial (see Fig. 12), oras shown by the cross sections of blades in Fig. 6, that part of the combined blade a farthest from the intake end may be curved in cross-section while the part of the blade nearest the intake end may be flat or warped from a flat plate.

The above description refers to fans in which the fluid operated on enters on one side only, but said description also applies to fans wherein it enters at both or opposite ends of the fan wheel, and which construc tion is known as double intake, by merely considering each double intake fan as con-- sisting of two separate single intake fans so connected together that their intake ends point oppositely, with the blades suitably adjusted for clockwise rotation in the one, and for anti-clockwise rotation in the other.

What I claim and desire to secure by Letters Patent is v 1. A centrifugal fan wheel of the multiblade drum type, comprising twisted blades the outer edges of which extend forwardly in a helical curve from the inlet end to the opposite end.

2. A centrifugal fan wheel of the multiblade drum type, comprising blades which at the disk, end have their outer edges in advance of their inner edges, and twisted so that in approacl'iing the inlet end such advance progressively diminishes.

3. A centrifugal fan wheel of the multiblade drum typo, comprising blades curved in cross section with their concave sides in advance, and their outer edges loading, at the disk end, and twisted to progressively diminish such lead toward the intake end.

4. A centrifugal fan wheel of the multiblade drum type, comprising twisted blades the outer portions of which at the intake end are approximately radial, and at the disk end approximately tangential andv project forwardly.

wardly.

6*. A; centrifugal fa Wheel of the multiblade] drum type, comprising twisted blades curved incrosssection, their intake ends blade drum type,

intense having their inner edges in their disk endshaving their advance.

7. A centrifugal fan wheel of the multicomprising twisted blades curved in cross-section, their intake ends having their inner edges in advance and their outer portions approximately radial, and their disk ends having theirfbuter edges in advance.

8. A centrifugal fan or pump wherein the fluid isdrawn in axially and discharged circumferentially, comprising afan shaft, a disk mounted thereon, and blades extending substantially parallel with the axis so as to form a drum-like structure inclosi'og a central intake chamber, said blades havin their outer edges toward the disk end advanced beyond that portion of the outer edge which is nearest the intake end.

9. A centrifugal fan or pump wherein the fluid is drawn in axially and discharged circumferentially, comprising afan shaft, a disk mounted thereon, and blades extending substantially parallel wit 1 the axis so as to form a drum-like structure inclosing a central intake chamber, the outer edges of said blades being inclined forwardly progressively from the intake toward the disk end.

10. A centrifugal fan or pump wherein the fluid is drawn in axially and discharged circumferentially, comprising a fan shaft, a disk mounted thereon, and blades extending substantially parallel with the axis so as to form a drum-like. structure inclosing a central intake chamber, the outer edges of advance, and outer edges 1n said-blades being inclined forwardly pro-- gressively from the intake toward the disk end, and said blades twisted so that their inner edgesare inclined at a different angle.

.11. A centrifugal fan or pump wherein the fluid is drawn in axially and discharged oircuinferentially, comprising a fan shaft, :1 disk mounted thereon, and bladescxteuding substantially parallel with the axis so as to form a drum-like structure inclosing a central intake chamber, the outer and inner edges of the blades being inclined rela tively to the axis from one end to the other ,at opposite angles.

12. A centrifugal fan or pump wherein the fluid is drawn in axially and discharged circiunfercntially, comprising a fan shaft, a disk mounted thereon, and blades eat-ending substantially parallel with the so as to form a drum-like inner edges of the blades being inclined relatively to the axis from one end of thtrbiade to the other at opposite angles, the opposite inclinations meeting and crossing midway of the blade.

13. A centrifugal fan or pump wherein the fluid is drawn in axially and discharged circumferentially, ccmprising a fan shaft, :1 disk mounted thereon, and blades extending substantially parallel with the axis so as to form a drui dike structure inclosing a central intake chamber, and said blades being of helical formation.

14. A centrifugal fan or pump comprising' a series-of elongated blades arranged in drum form to form acentral intake chamher, and adapted to draw in the fluid axially and discharge it circumferentially, such blades having their disk ends inclined in the direction of rotation ton greater extent than their intake ends.

15. In a centrifugal fan or pump comprising a rotary member having numerous elongated blades arranged lengthwise in approximately axial direction and in substantially drum form so as to inclose within them a relatively large intake chamber, said blades having their outer edges at the disk end extended in the direction of rotation in advance of the same of the blades. a

In witness whereof, I have hereunto signed my name in the presence of two subscribing witnesses.

StldUEL CLElIAND DAVIDSQN. Witnesses lViLLLisi fumns'rus lViLLr-m WATsoN.

structure inclosing, a central intake chamber, the outer and.

lid

edges at the intake end 

